A common drive circuit type fast mechanical switch and control method thereof

Abstract

The present application relates to a common drive circuit type fast mechanical switch and a control method thereof, comprising N switch units, each of which comprises an opening coil, a closing coil, a repulsion disk, an insulating transmission rod and an arc extinguishing chamber; a static contact and a moving contact are arranged in the arc extinguishing chamber; the opening coil and the closing coil are arranged on both sides of the repulsion disk opposite to each other, and the repulsion disk, the insulating transmission rod and the moving contact are fixedly connected; the opening coils / closing coils of the N switch units are respectively connected in series / parallel; the repulsion disk drives the insulating transmission rod and the moving contact to move under the drive of the opening coil / closing coil to perform closing / opening operations; by connecting the driving coils of multiple switch units in series or in parallel, and controlling the driving coils using the same driving circuit and buffer circuit, this structure realizes the sharing of the driving circuit and buffer circuit of multiple switch units, which greatly reduces the volume of the electromagnetic repulsion mechanism in the mechanical switch, thereby improving the energy utilization efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of mechanical switch control, and in particular to a common drive circuit type fast mechanical switch and a control method thereof. Background Art

[0002] At present, in DC power grids, it is necessary to use DC circuit breakers that can break large currents within milliseconds to quickly cut off faulty equipment or lines to ensure the stable operation of the non-faulty parts of the DC system and improve system reliability. The mainstream solution of traditional DC circuit breakers is a hybrid DC circuit breaker solution that uses fast mechanical switches and power electronic devices in parallel. Fast mechanical switches based on electromagnetic repulsion mechanisms are widely used in DC circuit breakers due to their simple structure, short mechanical delay time, and fast opening speed.

[0003] In high-voltage, large-capacity equipment systems, DC circuit breakers need to use multiple fast mechanical switches connected in series and parallel to meet insulation and current requirements. However, each existing fast mechanical switch needs to be configured with an independent drive circuit and buffer circuit. On the one hand, this will lead to a complex structure and large size of the DC circuit breaker, which will significantly increase the cost. On the other hand, due to differences in the performance of components in the control and drive circuits, line length, transmission delay and other factors, the synchronization of the fast mechanical switches will be poor. For example, when multiple units are connected in series, the mechanical switch with fast opening will withstand higher transient overvoltages for a short time; when multiple units are connected in parallel, the mechanical switch with slow opening will withstand large transient overcurrents for a short time, which can easily cause the mechanical switch to extinguish the arc and reignite when the current passes through zero, resulting in failure of the DC circuit breaker to open, seriously affecting the safety and reliability of the entire system. Summary of the invention

[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present application provides a common drive circuit type fast mechanical switch and a control method thereof, which specifically adopts the following technical solutions:

[0005] A common drive circuit type fast mechanical switch, comprising N switch units;

[0006] Each of the switch units includes an opening coil, a closing coil, a repulsion disk, an insulating transmission rod and an arc extinguishing chamber;

[0007] The arc extinguishing chamber is provided with a static contact and a moving contact, the static contact is arranged opposite to the moving contact, and the static contact is fixedly connected to the inner wall of the arc extinguishing chamber;

[0008] The opening coil and the closing coil are arranged oppositely on both sides of the repulsion disk, and the repulsion disk is connected to the insulating transmission rod; one end of the insulating transmission rod passes through the opening coil and extends into the arc extinguishing chamber, and the insulating transmission rod is fixedly connected to the moving contact;

[0009] The opening coils of N switch units are connected in series / parallel, and the closing coils of N switch units are connected in series / parallel;

[0010] The repulsion disks of the N switch units are driven by the corresponding opening coils / closing coils to drive the insulating transmission rods to move, and the insulating transmission rods drive the moving contacts of the N switch units to perform closing / opening operations synchronously.

[0011] Optionally: the common drive circuit type fast mechanical switch includes a drive device, the drive device includes an energy supply, a DC power supply, a pulse capacitor, a first trigger thyristor and a second trigger thyristor, the DC power supply is connected in parallel with the pulse capacitor, and the energy supply is connected to the DC power supply; the positive electrode of the pulse capacitor is respectively connected to the anode of the first trigger thyristor and the cathode of the second trigger thyristor;

[0012] The cathode of the first trigger thyristor is connected to one end of the N opening coils connected in series / parallel, and the other end of the N opening coils connected in series / parallel is connected to the negative electrode of the pulse capacitor;

[0013] The anode of the second trigger thyristor is connected to one end of the N closing coils connected in series / parallel, and the other end of the N closing coils connected in series / parallel is connected to the negative electrode of the pulse capacitor.

[0014] Optionally, the common drive circuit type fast mechanical switch further comprises a control device, wherein the control device is connected to the gates of the first trigger thyristor and the second trigger thyristor respectively. The control device sends a pulse high level signal to the gates of the first trigger thyristor and the second trigger thyristor respectively, thereby controlling the first trigger thyristor and the second trigger thyristor to be turned on.

[0015] Optional: The equivalent inductance of the opening coil and the equivalent inductance of the closing coil in each switch unit are equal, that is, L Fi =L Hi (i=1,2,…N)=L.

[0016] Optional: When N switch units are connected in series, the total equivalent inductance of the opening coil / closing coil in the N switch units is L eq =NL.

[0017] Optional: When N switch units are connected in parallel, the total equivalent inductance of the opening coil / closing coil in the N switch units is L eq =L / N.

[0018] Optional: The capacitance of the pulse capacitor and the voltage of the DC power supply must satisfy:

[0019]

[0020] Where C is the capacitance of the pulse capacitor; U is the voltage of the DC power supply; T is the discharge period; L eq is the total equivalent inductance of the opening coil / closing coil; I is the peak value of the discharge current.

[0021] The present invention also discloses a control method, which is applicable to the above-mentioned common drive circuit type fast mechanical switch for single-point operation, and the method comprises the following steps:

[0022] N switch units are initialized, and the repulsion disks in the switch units are in the closed position;

[0023] The energy supply in the driving device supplies power to the DC power supply, and the DC power supply pre-charges the pulse capacitor to a voltage U0;

[0024] When the first preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor, the first trigger thyristor is turned on, and the pre-charged pulse capacitor discharges to the opening coil of the switch unit, the opening coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the opening coil pushes the repulsion disk to move, and then drives the contact to move away from the static contact through the insulating transmission rod;

[0025] When the second preset time is reached, the pulse capacitor discharges half a cycle, and the current of the first trigger thyristor is cut off at zero crossing. At this time, the voltage of the pulse capacitor reaches the reverse peak value U1;

[0026] When the third preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the second trigger thyristor, the second trigger thyristor is turned on, the pulse capacitor discharges to the closing coil, the closing coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the closing coil generates a repulsive force on the repulsion disk, and then the closing coil generates a buffer for the repulsion disk;

[0027] When the fourth preset time is reached, the closing coil current passes through zero and is cut off, and the pulse capacitor voltage reaches the positive peak value U2. At this time, the repulsion disk reaches the opening position, the moving contact and the static contact are in the opening state, and the opening operation is completed.

[0028] The present invention also discloses another control method, which is applicable to the above-mentioned common drive circuit type fast mechanical switch to perform single-on operation. Specifically, the method comprises the following steps:

[0029] N switch units are initialized, and the repulsion disks in the switch units are in the open position;

[0030] The energy supply in the driving device supplies power to the DC power supply, and the DC power supply pre-charges the pulse capacitor to a voltage U0;

[0031] When the first preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor, the first trigger thyristor is turned on, and the pre-charged pulse capacitor discharges to the opening coil of the switch unit, the opening coil generates a changing magnetic field, and the repulsion disk generates an induced electric field. At this time, the relative distance between the opening coil and the repulsion disk is greater than the threshold distance, and the repulsion disk does not move;

[0032] When the second preset time is reached, the pulse capacitor discharges half a cycle, and the current of the first trigger thyristor is cut off at zero crossing. At this time, the voltage of the pulse capacitor reaches the reverse peak value U1;

[0033] When the third preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the second trigger thyristor, the second trigger thyristor is turned on, the pulse capacitor discharges to the closing coil, the closing coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the closing coil generates a repulsive force on the repulsion disk, the closing coil pushes the repulsion disk to move, and then drives the contact to approach the static contact through the insulating transmission rod;

[0034] When the fourth preset time is reached, the closing coil current is cut off through zero, and the pulse capacitor voltage reaches the positive peak value U2;

[0035] When the fifth preset time is reached, the closing coil current passes through zero and is cut off, and the pulse capacitor voltage reaches the reverse peak value U3. At this time, the repulsion disk reaches the closing position, the moving contact and the static contact are in the closed state, and the closing operation is completed.

[0036] Optional: During the single-closing operation of the above-mentioned common drive circuit type fast mechanical switch, when the pulse capacitor voltage is at the positive peak value U2 and the relative distance between the opening coil and the repulsion disk is less than the threshold distance, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor, the first trigger thyristor is turned on, the pulse capacitor discharges to the opening coil, the opening coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the opening coil generates a repulsive force on the repulsion disk, and the opening coil generates a buffer for the repulsion disk.

[0037] Beneficial Effects

[0038] The technical solution of this application has the following beneficial effects:

[0039] (1) The common drive circuit type fast mechanical switch of the present application connects the drive coils of multiple switch units in series or in parallel and uses the same drive circuit and buffer circuit to control the drive coils. This structure realizes the sharing of the drive circuit and buffer circuit of multiple switch units, which greatly reduces the volume of the electromagnetic repulsion mechanism in the mechanical switch, thereby improving energy utilization efficiency.

[0040] (2) The control method of the present application can implement switch control on multiple switch units. Through synchronous trigger control, the action consistency of N switch units can be greatly improved, and the voltage and current tolerance performance of the mechanical switch can be improved, and the probability of the mechanical switch current crossing zero and extinguishing the arc and reigniting can be reduced, thereby improving the safety and reliability of the entire system.

[0041] (3) The common drive circuit type fast mechanical switch of the present application shares the drive circuit and buffer circuit of the mechanical switch, and the residual energy of the pulse capacitor in the drive circuit can be used for buffering energy supply. It does not need to set up an additional buffer circuit, thereby reducing the circuit setting cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the structure of a common drive circuit type fast mechanical switch using a series structure in an embodiment of the present application.

[0043] Figure 2 is an equivalent circuit diagram of a fast mechanical switch using a series structure in an embodiment of the present application.

[0044] Figure 3 Schematic diagram of the structure of a common drive circuit type fast mechanical switch using a parallel structure in an embodiment of the present application.

[0045] Figure 4 is an equivalent circuit diagram of a fast mechanical switch in a parallel structure in an embodiment of the present application.

[0046] Figure 5 Schematic diagram of the waveforms of the pulse capacitor voltage and current during single-point operation in an embodiment of the present application.

[0047] Figure 6 Schematic diagram of the waveforms of the pulse capacitor voltage and current during single-close operation in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The present application is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and cannot be used to limit the scope of protection of the present application. It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present application.

[0049] At present, the DC grid based on the flexible DC system has shown obvious advantages in large-capacity power transmission, distributed energy access, and reactive power support of AC systems, and is an important development direction for future power grids. In the DC grid, it is necessary to use DC circuit breakers that can break large currents within milliseconds to quickly remove faulty equipment or lines to ensure the stable operation of the non-faulty parts of the DC system and improve system reliability.

[0050] Among the various topological structures of DC circuit breakers at present, a hybrid DC circuit breaker solution that connects fast mechanical switches and power electronic devices in parallel is usually adopted, which has the advantages of strong breaking capacity and fast breaking speed. Hybrid DC circuit breakers require that the mechanical switch can achieve rapid contact separation to facilitate the transfer of current to the transfer branch. At the same time, the mechanical switch can obtain the largest possible initial speed to form an insulation gap as quickly as possible to withstand the transient recovery overvoltage that appears in the insulation gap. Fast mechanical switches based on electromagnetic repulsion mechanisms are widely used in hybrid DC circuit breakers because they have the advantages of simple structure, short mechanical delay time, and fast opening speed.

[0051] In addition, in high-voltage, large-capacity systems, hybrid DC circuit breakers use multiple switch units connected in series and parallel to meet insulation and current requirements, while each traditional electromagnetic repulsion-type fast mechanical switch needs to be equipped with an independent drive circuit and buffer circuit. On the one hand, this structure will cause the DC circuit breaker to have a complex structure, large size, and significantly increase the cost. On the other hand, due to differences in the performance of components in the control and drive circuits, line length, transmission delay and other factors, the fast mechanical switches will have poor synchronization. Mechanical switches with fast opening speed will withstand higher transient overvoltages for a short time (in high-voltage application conditions, when multiple mechanical switches are connected in series), and mechanical switches with slow opening speed will withstand large transient overcurrents for a short time (in high-current application conditions, when multiple mechanical switches are connected in parallel), which can easily cause the mechanical switch to extinguish the arc and reignite at the current zero point, resulting in failure of the DC circuit breaker to open, seriously affecting the safety and reliability of the entire system.

[0052] In order to overcome the above-mentioned shortcomings, the present application improves the drive circuit control method, makes full use of the residual energy of the pulse capacitor, and realizes the sharing of the drive circuit and buffer circuit of a single fast mechanical switch; at the same time, the opening coils and closing coils of multiple switch units are connected in series or in parallel, and the drive circuit control mode and parameters are flexibly adjusted to realize the sharing of the drive circuit and buffer circuit of multiple switches.

[0053] Specifically, Figures 1 to 4 As shown, the present application discloses a common drive circuit type fast mechanical switch, which includes N switch units; each of the switch units includes an opening coil 3, a closing coil 5, a repulsion disk 4, an insulating transmission rod 2 and an arc extinguishing chamber 1. In the present application, the opening coil 3 and the closing coil 5 are mainly used to generate a changing magnetic field, and the repulsion disk 4 is usually made of metal. Under the action of the changing magnetic field of the opening coil 3 / closing coil 5, the repulsion disk 4 generates an induced current. Since the magnetic field of the induced current is opposite to the direction of the changing magnetic field, a repulsion force is generated between the coil and the repulsion disk 4, pushing the repulsion disk 4 to move. The insulating transmission rod 2 is made of an insulating material. The insulating transmission rod 2 can transmit the action of the repulsion disk 4 to the moving contact of the arc extinguishing chamber 1. The switching action can be realized by the contact or separation of the moving contact and the static contact to realize the function of switching on and off current.

[0054] Specifically, the arc extinguishing chamber 1 is provided with a cavity, which can quickly extinguish the arc and suppress the current after the medium and high voltage circuit is cut off from the power supply through the excellent insulation of the vacuum in the tube, so as to avoid accidents and unexpected events. The arc extinguishing chamber 1 described in the present application is provided with a static contact and a moving contact, the static contact is arranged opposite to the moving contact, and the static contact is fixedly connected to the inner wall of the arc extinguishing chamber 1, and the moving contact can be close to or away from the static contact.

[0055] Furthermore, the opening coil 3 and the closing coil 5 are arranged on both sides of the repulsion disk 4, and a moving gap of a certain distance is provided between the opening coil 3 and the closing coil 5, and the repulsion disk 4 can move in the moving gap. In addition, the repulsion disk 4 is connected to the insulating transmission rod 2, one end of the insulating transmission rod 2 passes through the opening coil 3 and extends into the arc extinguishing chamber 1, and the insulating transmission rod 2 is fixedly connected to the moving contact. When the repulsion disk 4 is close to the opening coil 3, and the opening coil 3 is energized to generate a changing magnetic field, the repulsion disk 4 is affected by the changing magnetic field and generates an induced current, and the induced current will then generate an induced magnetic field. Under the action of the two magnetic fields, the repulsion disk 4 will be subjected to repulsion, causing the repulsion disk 4 to move away from the opening coil 3. Similarly, when the repulsion disk 4 is close to the closing coil 5 and the closing coil 5 is energized to generate a changing magnetic field, the repulsion disk 4 will be affected by the changing magnetic field of the closing coil 5 and be subjected to repulsion, causing the repulsion disk 4 to move away from the closing coil 5. In the present application, the repulsion disk 4 can be controlled to move freely in the moving gap by controlling the energization timing of the opening coil 3 and the closing coil 5.

[0056] In addition, in order to realize the synchronous action of N switch units in the present application, the opening coils 3 of the N switch units are connected in series / parallel, and the closing coils 5 of the N switch units are connected in series / parallel; the repulsion disks 4 of the N switch units are respectively driven by the corresponding opening coils 3 / closing coils 5 to drive the insulating transmission rod 2 to move, and the insulating transmission rod 2 drives the moving contacts of the N switch units to synchronously perform closing / opening operations.

[0057] In addition, in the present application, each switch unit is further provided with a holding mechanism 6, which is used to fix the position of the repulsion disk after the closing / opening operation is completed. Usually, the holding mechanism 6 can be a compression spring, for example, a plurality of compression springs are radially arranged around the insulating transmission rod, and pressure is applied to the insulating transmission rod by the compression spring to keep the insulating transmission rod from axial movement.

[0058] It should be noted that in this application, when multiple opening coils 3 / closing coils 5 are connected in series, the equivalent inductance and equivalent resistance of the coils are large, and a smaller pulse capacitor C can be configured. When charging the pulse capacitor C, the applied voltage needs to be increased, and in the discharge stage, the remaining voltage of the pulse capacitor C is relatively low; when multiple opening coils 3 / closing coils 5 are connected in parallel, the equivalent inductance and equivalent resistance of the coils are small, and a larger pulse capacitor C can be configured. When charging the pulse capacitor C, the applied voltage can be appropriately reduced, and in the discharge stage, the remaining voltage of the pulse capacitor C is relatively high. Therefore, when selecting the coil connection method, this application can be selected according to the required voltage and current requirements.

[0059] Furthermore, the common drive circuit type fast mechanical switch also includes a drive device 7 and a control device 8. The drive device 7 is responsible for energizing the opening coil 3 / closing coil 5, and the control device 8 is used for triggering control of thyristors SCR1 and SCR2 in the drive circuit. The control device is connected to the drive device via an optical fiber.

[0060] For the case where N switch units are connected in series:

[0061] Specifically, Figure 1 and Figure 2 As shown, the driving device includes an energy supply S, a DC power supply U, a pulse capacitor C, a first trigger thyristor SCR1 and a second trigger thyristor SCR2. The DC power supply U is connected in parallel with the pulse capacitor C, and the energy supply S is connected to the DC power supply U; the positive electrode of the pulse capacitor C is respectively connected to the anode of the first trigger thyristor SCR1 and the cathode of the second trigger thyristor SCR2. The opening coils 3 of the N switch units are sequentially connected in series to form an opening coil 3 combination, and the closing coils 5 of the N switch units are also sequentially connected in series to form a closing coil 5 combination. When the coils are energized, the N opening coils 3 / closing coils 5 in series will be energized at the same time. The cathode of the first trigger thyristor SCR1 is connected to one end of the opening coil 3 combination, and the other end of the opening coil 3 combination is connected to the negative electrode of the pulse capacitor C. The anode of the second trigger thyristor SCR2 is connected to one end of the closing coil 5 combination, and the other end of the closing coil 5 combination is connected to the negative electrode of the pulse capacitor C. This series connection method is suitable for high voltage application conditions.

[0062] Combination Figure 2As shown, the driving device is provided with three external interfaces: interface terminal a, interface terminal b, and interface terminal c, wherein interface terminal a corresponds to the cathode of the first trigger thyristor SCR1, and one terminal of the opening coil 3 combination can be connected through interface terminal a; interface terminal b corresponds to the anode of the second trigger thyristor SCR2, and one terminal of the closing coil 5 combination can be connected through interface terminal b; and interface terminal c corresponds to the negative electrode of the pulse capacitor C, and the other end of the opening coil 3 combination and the closing coil 5 combination can be connected in parallel through terminal c.

[0063] Furthermore, the control device is connected to the gates of the first trigger thyristor SCR1 and the second trigger thyristor SCR2 respectively. The control device sends pulse high level signals to the gates of the first trigger thyristor SCR1 and the second trigger thyristor SCR2 respectively, so as to control the first trigger thyristor SCR1 and the second trigger thyristor SCR2 to be turned on.

[0064] It should be noted that in order to ensure that the mechanical characteristics of the N switch units meet the requirements of the DC circuit breaker, it is necessary to ensure that the amplitude and discharge cycle of the coil current during the operation of each switch unit meet the requirements. Figure 2 As shown in the equivalent electrical diagram of the driving circuit of the common driving circuit type fast mechanical switch in the present application, L F1 ~L FN They represent the equivalent inductance of the opening coil 3 of the first switch unit to the Nth switch unit, L H1 ~L HN The equivalent inductance of the closing coil 5 of the first switch unit to the Nth switch unit is respectively represented. The equivalent inductance of the opening coil 3 in each switch unit is equal to the equivalent inductance of the closing coil 5, that is, L Fi =L Hi (i=1,2,…N)=L. When N switch units are connected in series, the total equivalent inductance of the opening coil 3 / closing coil 5 in the N switch units is L eq =NL.

[0065] Furthermore, when N switch units are connected in series, the capacitance of the pulse capacitor C and the voltage of the DC power supply U need to satisfy the following conditions:

[0066]

[0067] Where C is the capacitance of the pulse capacitor C; U is the voltage of the DC power supply U; T is the discharge period; L eq is the total equivalent inductance of the opening coil 3 / closing coil 5; I is the peak value of the discharge current.

[0068] When adapting the parameters of the driving circuit, first determine the capacitance C of the pulse capacitor C according to the discharge period T requirement, and then determine the capacitor pre-charge voltage U according to the discharge current peak value I requirement.

[0069] For the case where N switch units are connected in parallel:

[0070] like Figure 3 and Figure 4 As shown, the driving device 7 also includes an energy supply S, a DC power supply U, a pulse capacitor C, a first trigger thyristor SCR1 and a second trigger thyristor SCR2. The DC power supply U is connected in parallel with the pulse capacitor C, and the energy supply S is connected to the DC power supply U; the positive electrode of the pulse capacitor C is respectively connected to the anode of the first trigger thyristor SCR1 and the cathode of the second trigger thyristor SCR2. The opening coils 3 of the N switch units are connected in parallel in sequence to form an opening coil 3 combination, and the closing coils 5 of the N switch units are also connected in parallel in sequence to form a closing coil 5 combination; the cathode of the first trigger thyristor SCR1 is connected to one end of the opening coil 3 combination, and the other end of the opening coil 3 combination is connected to the negative electrode of the pulse capacitor C. The anode of the second trigger thyristor SCR2 is connected to one end of the closing coil 5 combination, and the other end of the closing coil 5 combination is connected to the negative electrode of the pulse capacitor C. This parallel connection method is suitable for large current application conditions.

[0071] Combination Figure 4 As shown, the driving device 7 is provided with three external interfaces: interface terminal a, interface terminal b, and interface terminal c, wherein interface terminal a corresponds to the cathode of the first trigger thyristor SCR1, and one terminal of the opening coil 3 combination can be connected through interface terminal a; interface terminal b corresponds to the anode of the second trigger thyristor SCR2, and one terminal of the closing coil 5 combination can be connected through interface terminal b; and interface terminal c corresponds to the negative electrode of the pulse capacitor C, and the other end of the opening coil 3 combination and the closing coil 5 combination can be connected in parallel through terminal c.

[0072] Furthermore, the control device 8 is connected to the gates of the first trigger thyristor SCR1 and the second trigger thyristor SCR2 respectively. The control device sends pulse high level signals to the gates of the first trigger thyristor SCR1 and the second trigger thyristor SCR2 respectively, so as to control the first trigger thyristor SCR1 and the second trigger thyristor SCR2 to be turned on.

[0073] It should be noted that in order to ensure that the mechanical characteristics of the N switch units meet the requirements of the DC circuit breaker, it is necessary to ensure that the amplitude and discharge cycle of the coil current during the operation of each switch unit meet the requirements. Figure 4 As shown in the equivalent electrical diagram of the driving circuit of the common driving circuit type fast mechanical switch in the present application, L F1 ~L FN They represent the equivalent inductance of the opening coil 3 of the first switch unit to the Nth switch unit, L H1 ~L HNThe equivalent inductance of the closing coil 5 of the first switch unit to the Nth switch unit is respectively represented. The equivalent inductance of the opening coil 3 in each switch unit is equal to the equivalent inductance of the closing coil 5, that is, L Fi =L Hi (i=1,2,…N)=L. When N switch units are connected in parallel, the total equivalent inductance of the opening coil 3 / closing coil 5 in the N switch units is L eq =L / N.

[0074] Furthermore, when N switch units are connected in parallel, the capacitance of the pulse capacitor C and the voltage of the DC power supply U need to satisfy the following conditions:

[0075]

[0076] Where C is the capacitance of the pulse capacitor C; U is the voltage of the DC power supply U; T is the discharge period; L eq is the total equivalent inductance of the opening coil 3 / closing coil 5; I is the peak value of the discharge current.

[0077] When adapting the parameters of the driving circuit, first determine the capacitance C of the pulse capacitor C according to the discharge period T requirement, and then determine the capacitor pre-charge voltage U according to the discharge current peak value I requirement.

[0078] In general, the common drive circuit type fast mechanical switch of the present application realizes the sharing of the drive circuit of each switch unit by connecting the drive coils of multiple switch units in series or in parallel, which can greatly reduce the volume and cost of the repulsion mechanism. In the existing DC circuit breaker, usually N switch units need to be respectively configured with N sets of drive circuits and buffer circuits (the pulse capacitor C and high-voltage DC power supply U in the buffer device need to be configured in 2N sets), and the control device needs to control each drive circuit and buffer circuit respectively. The timing coordination between the N switches is difficult and the synchronization is poor, which will affect the breaking performance of the DC circuit breaker. The mechanical switch is prone to reignition at the moment of zero arc extinction. The present application realizes the sharing of the drive circuit by connecting the drive coils in series or in parallel, which can save N-1 sets of drive circuits and N sets of buffer circuits.

[0079] In addition, in the hybrid high-voltage DC circuit breaker, the reclosing operation is mainly completed by the power electronic switch, so the action requirements of the switch unit are mainly single-opening operation and single-closing operation. For these two working conditions, this application provides specific control methods respectively. It should be noted that the closing position in this application refers to the position of the repulsion disk 4 when the static contact and the moving contact are in contact, and the opening position refers to the position of the repulsion disk 4 when the static contact and the moving contact are at the maximum separation distance.

[0080] For single-break operation (N switch units are initially in the closed position):

[0081] Combination Figure 5As shown, the present application discloses a control method, which includes the following steps:

[0082] First, N switch units are initialized, and the repulsion disk 4 in the switch unit is in the closed position;

[0083] Then the energy supply S in the driving device supplies power to the DC power supply U, and the DC power supply U pre-charges the pulse capacitor C to a voltage of U0;

[0084] When the first preset time is reached, i.e., time t0, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor SCR1, the first trigger thyristor SCR1 is turned on, and the pre-charged pulse capacitor C discharges to the opening coil 3 of the switch unit, the opening coil 3 generates a changing magnetic field, the repulsion disk 4 generates an induced electric field, the opening coil 3 pushes the repulsion disk 4 to move, and then drives the contact to move away from the static contact through the insulating transmission rod 2;

[0085] When the second preset time is reached, i.e., time t1, since the first trigger thyristor SCR1 is a unidirectional thyristor, the pulse capacitor C has been discharged for half a cycle, and the current of the first trigger thyristor SCR1 is cut off at zero crossing. At this time, the voltage of the pulse capacitor C reaches the reverse peak value U1;

[0086] When the third preset time is reached, i.e., time t2, the control device sends a narrow pulse high-level signal to the gate of the second trigger thyristor, the second trigger thyristor is turned on, the pulse capacitor C discharges to the closing coil 5, the closing coil 5 generates a changing magnetic field, the repulsion disk 4 generates an induced electric field, the closing coil 5 generates a repulsive force on the repulsion disk 4, and then the closing coil 5 generates a buffer for the repulsion disk 4;

[0087] When the fourth preset time is reached, that is, time t3, the current of the closing coil 5 is cut off at zero crossing, and the voltage of the pulse capacitor C reaches the positive peak value U2. At this time, the repulsion disk 4 reaches the opening position, the moving contact and the static contact are in the opening state, and the opening operation is completed.

[0088] For single-close operation (N switch units are initially in the open position):

[0089] Combination Figure 6 As shown, the present invention also discloses another control method, specifically, the method comprises the following steps:

[0090] First, N switch units are initialized, and the repulsion disk 4 in the switch unit is in the open position;

[0091] Then the energy supply S in the driving device supplies power to the DC power supply U, and the DC power supply U pre-charges the pulse capacitor C to a voltage of U0;

[0092] When the first preset time is reached, that is, at time t0, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor SCR1, the first trigger thyristor SCR1 is turned on, and the pre-charged pulse capacitor C discharges to the opening coil 3 of the switch unit, the opening coil 3 generates a changing magnetic field, and the repulsion disk 4 generates an induced electric field. At this time, the relative distance between the opening coil 3 and the repulsion disk 4 is greater than the threshold distance, and the repulsion disk 4 does not move;

[0093] When the second preset time is reached, i.e., time t1, the pulse capacitor C discharges half a cycle, and the current of the first trigger thyristor SCR1 passes through zero and is cut off. At this time, the voltage of the pulse capacitor C reaches the reverse peak value U1;

[0094] When the third preset time is reached, i.e., time t2, the control device sends a narrow pulse high-level signal to the gate of the second trigger thyristor SCR2, the second trigger thyristor SCR2 is turned on, the pulse capacitor C discharges to the closing coil 5, the closing coil 5 generates a changing magnetic field, the repulsion disk 4 generates an induced electric field, the closing coil 5 generates a repulsive force on the repulsion disk 4, the closing coil 5 pushes the repulsion disk 4 to move, and then drives the contact to approach the static contact through the insulating transmission rod 2;

[0095] When the fourth preset time is reached, i.e., time t3, the current of the closing coil 5 is cut off through zero, and the voltage of the pulse capacitor C reaches the positive peak value U2;

[0096] When the fifth preset time is reached, i.e., time t5, the current of the closing coil 5 passes through zero and is cut off, and the voltage of the pulse capacitor C reaches the reverse peak value U3. At this time, the repulsion disk 4 reaches the closing position, the moving contact and the static contact are in the closed state, and the closing operation is completed.

[0097] Furthermore, in the single-closing operation of the above-mentioned common drive circuit type fast mechanical switch, under certain working conditions, the closing speed requirement is high, and buffering is required in the closing stage. When the voltage of the pulse capacitor C is at the positive peak value U2, and the relative distance between the opening coil 3 and the repulsion disk 4 is less than the threshold distance, that is, at time t4, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor SCR1, the first trigger thyristor SCR1 is turned on, the pulse capacitor C discharges to the opening coil 3, the opening coil 3 generates a changing magnetic field, the repulsion disk 4 generates an induced electric field, the opening coil 3 generates a repulsive force on the repulsion disk 4, and then the opening coil 3 generates a buffer on the repulsion disk 4.

[0098] In general, since a single fast mechanical switch in the prior art needs to be equipped with an independent drive circuit and a buffer circuit (the pulse capacitor C and the high-voltage DC power supply U in the buffer device need to be configured in two sets), each is triggered separately, the energy utilization rate is low, and the volume and cost are relatively high. However, the above control method in this application can make full use of the residual energy of the pulse capacitor C by optimizing the drive circuit, realize the sharing of the drive circuit and the buffer circuit of each switch unit, greatly reduce the volume and cost of the electromagnetic repulsion mechanism, and improve the energy utilization rate.

[0099] In addition, the existing control device needs to trigger the thyristors of N drive circuits. Due to differences in component performance, line length, transmission delay and other factors, the synchronization of the switch units will be poor. The switch units with fast opening will withstand higher transient overvoltages for a short time (high voltage application conditions, when multiple mechanical switches are connected in series), and the switch units with slow opening will withstand large transient overcurrents for a short time (high current application conditions, when multiple mechanical switches are connected in parallel), which can easily cause the switch units to extinguish arcs and reignite at the current zero crossing point, resulting in failure of the DC circuit breaker to break, seriously affecting the safety and reliability of the entire system. The control method of the present application can greatly improve the consistency of the actions of N switch units through synchronous triggering control, improve the voltage and current tolerance performance of the switch units, and reduce the probability of the switch units extinguishing arcs and reigniting when the current passes through zero.

[0100] Furthermore, the present application also discloses a non-volatile storage medium, wherein the non-volatile storage medium includes a stored program, wherein when the program is executed, the device where the non-volatile storage medium is located is controlled to execute the above-mentioned control method.

[0101] In addition, the present application also discloses an electronic device, comprising a processor and a memory; the memory stores computer-readable instructions, and the processor is used to execute the computer-readable instructions, wherein the computer-readable instructions execute the above-mentioned control method when they are executed.

[0102] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable non-transient storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0103] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0104] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0105] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0106] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A control method for a common drive circuit type fast mechanical switch, the common drive circuit type fast mechanical switch comprises N switch units; each of the switch units comprises an opening coil, a closing coil, a repulsion disk, an insulating transmission rod and an arc extinguishing chamber; a static contact and a moving contact are arranged in the arc extinguishing chamber, the static contact is arranged opposite to the moving contact, and the static contact is fixedly connected to the inner wall of the arc extinguishing chamber; the opening coil and the closing coil are arranged opposite to each other on both sides of the repulsion disk, and the repulsion disk is connected to the insulating transmission rod; one end of the insulating transmission rod passes through the opening coil and extends into the arc extinguishing chamber, and the insulating transmission rod is fixedly connected to the moving contact; the opening coils of the N switch units are connected in series / parallel, and the closing coils of the N switch units are connected in series / parallel; the repulsion disks of the N switch units are driven by the corresponding opening coils / closing coils to drive the insulating transmission rods to move, and the insulating transmission rods drive the moving contacts of the N switch units to close / open synchronously; characterized in that The control method comprises the following steps: N switch units are initialized, and the repulsion disks in the switch units are in the closed position; The energy supply in the driving device supplies power to the DC power supply, and the DC power supply pre-charges the pulse capacitor to a voltage U0; When the first preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor, the first trigger thyristor is turned on, and the pre-charged pulse capacitor discharges to the opening coil of the switch unit, the opening coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the opening coil pushes the repulsion disk to move, and then drives the contact to move away from the static contact through the insulating transmission rod; When the second preset time is reached, the pulse capacitor discharges half a cycle, and the current of the first trigger thyristor is cut off at zero crossing. At this time, the voltage of the pulse capacitor reaches the reverse peak value U1; When the third preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the second trigger thyristor, the second trigger thyristor is turned on, the pulse capacitor discharges to the closing coil, the closing coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the closing coil generates a repulsive force on the repulsion disk, and then the closing coil generates a buffer for the repulsion disk; When the fourth preset time is reached, the closing coil current passes through zero and is cut off, and the pulse capacitor voltage reaches the positive peak value U2. At this time, the repulsion disk reaches the opening position, the moving contact and the static contact are in the opening state, and the opening operation is completed.

2. A control method for a common drive circuit type fast mechanical switch, the common drive circuit type fast mechanical switch comprises N switch units; each of the switch units comprises an opening coil, a closing coil, a repulsion disk, an insulating transmission rod and an arc extinguishing chamber; a static contact and a moving contact are arranged in the arc extinguishing chamber, the static contact is arranged opposite to the moving contact, and the static contact is fixedly connected to the inner wall of the arc extinguishing chamber; the opening coil and the closing coil are arranged opposite to each other on both sides of the repulsion disk, and the repulsion disk is connected to the insulating transmission rod; one end of the insulating transmission rod passes through the opening coil and extends into the arc extinguishing chamber, and the insulating transmission rod is fixedly connected to the moving contact; the opening coils of the N switch units are connected in series / parallel, and the closing coils of the N switch units are connected in series / parallel; the repulsion disks of the N switch units are driven by the corresponding opening coils / closing coils to drive the insulating transmission rods to move, and the insulating transmission rods drive the moving contacts of the N switch units to close / open synchronously; characterized in that The control method comprises the following steps: N switch units are initialized, and the repulsion disks in the switch units are in the open position; The energy supply in the driving device supplies power to the DC power supply, and the DC power supply pre-charges the pulse capacitor to a voltage U0; When the first preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor, the first trigger thyristor is turned on, and the pre-charged pulse capacitor discharges to the opening coil of the switch unit, the opening coil generates a changing magnetic field, and the repulsion disk generates an induced electric field. At this time, the relative distance between the opening coil and the repulsion disk is greater than the threshold distance, and the repulsion disk does not move; When the second preset time is reached, the pulse capacitor discharges half a cycle, and the current of the first trigger thyristor is cut off at zero crossing. At this time, the voltage of the pulse capacitor reaches the reverse peak value U1; When the third preset time is reached, the control device sends a narrow pulse high-level signal to the gate of the second trigger thyristor, the second trigger thyristor is turned on, the pulse capacitor discharges to the closing coil, the closing coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the closing coil generates a repulsive force on the repulsion disk, the closing coil pushes the repulsion disk to move, and then drives the contact to approach the static contact through the insulating transmission rod; When the fourth preset time is reached, the closing coil current is cut off through zero, and the pulse capacitor voltage reaches the positive peak value U2; When the fifth preset time is reached, the closing coil current passes through zero and is cut off, and the pulse capacitor voltage reaches the reverse peak value U3. At this time, the repulsion disk reaches the closing position, the moving contact and the static contact are in the closed state, and the closing operation is completed.

3. The control method according to claim 1 or 2, characterized in that: The driving device comprises an energy supply, a DC power supply, a pulse capacitor, a first trigger thyristor and a second trigger thyristor, wherein the DC power supply is connected in parallel with the pulse capacitor, and the energy supply is connected to the DC power supply; the positive electrode of the pulse capacitor is connected to the anode of the first trigger thyristor and the cathode of the second trigger thyristor respectively; The cathode of the first trigger thyristor is connected to one end of the N opening coils connected in series / parallel, and the other end of the N opening coils connected in series / parallel is connected to the negative electrode of the pulse capacitor; The anode of the second trigger thyristor is connected to one end of N closing coils connected in series / parallel, and the other end of the N closing coils connected in series / parallel is connected to the negative electrode of the pulse capacitor.

4. The control method according to claim 3, characterized in that: The invention also comprises a control device, wherein the control device is connected to the gate of the first trigger thyristor and the gate of the second trigger thyristor respectively.

5. The control method according to claim 1 or 2, characterized in that: The equivalent inductance of the opening coil and the equivalent inductance of the closing coil in each switch unit are equal, that is, L Fi =L Hi (i=1,2,…N)=L .

6. The control method according to claim 5, characterized in that: When N switch units are connected in series, the total equivalent inductance of the opening coil / closing coil in the N switch units is L eq = NL .

7. The control method according to claim 5, characterized in that: When N switch units are connected in parallel, the total equivalent inductance of the opening coil / closing coil in the N switch units is L eq = L / N .

8. The control method according to claim 3, characterized in that: The capacitance of the pulse capacitor and the voltage of the DC power supply must meet the following conditions: ; in C is the capacitance value of the pulse capacitor; U is the voltage value of the DC power supply; T is the discharge cycle; L eq is the total equivalent inductance of the opening coil / closing coil; I is the peak value of the discharge current.

9. The control method according to claim 2, characterized in that: When the pulse capacitor voltage reaches the positive peak value U2 and the relative distance between the opening coil and the repulsion disk is less than the threshold distance, the control device sends a narrow pulse high-level signal to the gate of the first trigger thyristor, the first trigger thyristor is turned on, the pulse capacitor discharges to the opening coil, the opening coil generates a changing magnetic field, the repulsion disk generates an induced electric field, the opening coil generates a repulsive force on the repulsion disk, and the opening coil generates a buffer for the repulsion disk.

Images